Something is draining power from the battery when the car is off. If I don't start the car for about 4 days the battery is dead, dead, dead (I can't even pop the trunk). Once I get a jump start and recharge it everything is fine.

Here are some key points:
1. The battery is brand new. This issue eventually killed the previous battery.
2. The alternator is about 1 year old.
3. There are no visible lights on anywhere.

More backstory... I used a Voltage Meter to check the fuses and the alternator. Ran it between the -ve batt post and the -ve batt cable. The VM read about 12.5. Pulled each fuse one by one but the only one that made any difference was a 70A fuse labelled 'Battery' that made the reading drop to about 11. Is that normal?

For the alternator, I disconnected the only two wires coming into it. There was a small one on the side (near the top) that lead to the battery, and a combo plug at the back which lead to a large electronic cluster. Then I checked the battery voltage again and it was still about 12.5. Also, just in case there was something funky with the neg battery cable I also grounded the VM on the engine block instead of the -ve terminal while checking voltage and that didn't change the reading.

I have also checked for case drain, just in case, but there was none.

Hope someone can help.

I think you might be better using an ammeter connected the way you described.
As long as there’s any form of connection or power usage, a voltmeter will show a reading.
Things like the memory’s of the different computers, clock and radio are always using some form of power.
All of these different memory’s shouldn’t add up too anymore then about .025 of an amp, at the very most.
With the ammeter connected, start over again, disconnecting anything/everything you can get too, until you see an amperage drop.
While doing this remember that if a door is open; you might be turning on things; interior/dome light for one example.
On some vehicles, you have to wait a number of minutes after turning the ignition off or closing doors for the different devices to go to sleep.
In other words, the internal timer of a control module may take up to 20 minutes to completely shut down.
So don’t be too quick to condemn something, after pulling a fuse or disconnecting a unit.

Once you find a suspicious circuit(s) that might be causing the problem; you’ll have too read up on their principles of operation.
Confirming how long they should or shouldn’t be drawing current.

It’s too bad that we can’t see electricity or current flow, like coolant or oil leaks; it would make life so much easier. LOL


Dan.

Canadian "EH"

Hi Dan,
I have one of those Multi-Meters and it does have a section for ~mA which I assume is for milliAmps. It has settings for 0.5, 10, 250, & 1.5V. And I'm guessing, based on your post, that I should set it to 250 mA -- .025 Amp = 25 mA, right?
Thanks for your help.
Paul.

That'll work.

Dan.

Canadian "EH"

Hi Dan,
I set the Multi-Meter to 250 mAmps, then disconnected the -ve battery cable and hooked the Meter between the -ve battery post and the -ve battery cable. When I closed the circuit (-ve Meter terminal to -ve battery post and +ve terminal to ground), it blew the fuse on the Meter. I replaced the fuse but it blew it again. What did I do wrong?
I don't know much about the difference between Volts and Amps, but if there is a reading of 12.5 Volts how can we measure milliAmps?
Frustrated & Confused,
Paul.

In Reply To

What is the maximum amperage rating for this meter? The meter I use here at the shop is a 10 amp max.
What might be going on here is, when you make that connection, a number of modules will initially come on line and then shut down, when it/they don’t see the ignition switch on. This initial draw may be well above your meters rating thus blowing the fuse?
What I do in these cases is before I connect the ammeter; I connect a jumper wire between the battery and the battery cable terminal. Let everybody wake up and then wait for a couple of minutes for everyone to go back to sleep. I then connect the ammeter and remove the jumper wire.
If whatever is drawing on the battery is below the meters rating; the fuse should hold.
Now don’t forget that if you turn something on, like your headlights or the ignition switch, you’ll pop the fuse again.
Something else you can do and this is just to verify that the meter and the meter connections are good; is turn on the dome light or glove box light. The light should light and you’ll see the amperage draw of that light bulb on the meter. Most single filament bulbs will draw anywhere from 1 – 1.5 amps.

Dan.

Canadian "EH"